Combined electromagnetic control device with small travel armature and motion increasing means therefor



April 21, 1953 h s. KARRER 2,635,637

COMBINED ELECTROMAGNETIC CONTROL DEVICE WITH SMALL TRAVEL ARMATURE AND MOTION INCREASING MEANS THEREFOR Filed April 22, 1949 2 SHEETS-SHEET 1 $1 k INVENTOR.

Sebgsi'ian liar/ 6f BY JWW. Jamal/ m Patented Apr. 21, 1953 COMBINED ELECTROMAGNETIC CONTROL DEVICE WITH SMALL TRAVEL ARMATURE AND MOTION INCREASING MEANS THEREFOR Sebastian Karrer, Milwaukee, Wis., assignor to Milwaukee Gas Specialty Company, Milwaukee, Wis., a corporation of Wisconsin Application April 22, 1949, Serial No. 89,099

12 Claims.

This invention relates, in general, to thermoelectrically actuated devices, and has particular relation to thermoelectrically actuated valves, relays, and the like.

Thermoelectric control devices having a thermoelectric generator, the hot junction or junctions of which are heated by a pilot burner or other flame whereby to energize an electromagnet having a coil connected in circuit with the thermoelectric generator, to hold an armature in attracted position, and a valve or other controlling member in open or operating position, have been previously provided. The thermoelectric power generated by the heating of the "hot junction or junctions of such devices has not, however, been sufficient for actuation of the controlling means from one position to another position, particularly a fluid control valve, an amount to provide for opening and closing the same sufficiently for its intended purpose.

One of the main objects of the present invention is to provide an improved form of ther moelectrically actuated device in which the armature moves only a very minute amount (i. e., an amount that can be accomplished by heating the hot junction or junctions of the thermoelectric generator), and in which the minute movement of the armature provides for increased movement of the valve, relay member, or other controlling means in amount, for example, for opening and closing of the valve sufliciently for its intended purpose, or for movement of other controlling means a useful amount.

Another object of the invention is to provide a device having a body of liquid or'other suitable fluid for providing, by minute movement of the armature, an increased amount of movement of the valve, relay member, or other controlling means, and more particularly, in which different cross-sectional areas of the liquid or other fluid containing chamber at the armature and at the controlling position provide for the increased movement of the valve, relay member, or other controlling means.

Another object of the invention is to provide in a device of the class described means for filling a large portion of the chamber of large crosssectional area adjacent to the armature and for reducing any volumetric variations in the liquid or fluid body due to changes in ambient temperature.

Another object of the invention is to provide a device of the class described in which there is a diaphragm closing the large cross-sectional area of the liquid or other fluid containing chamto control a switch or relay; and

her adjacent to the armature, and more particularly a device in which there is a second diaphragm which cooperates in the tubular system and in such manner that changes in atmospheric pressure affecting the first-mentioned diaphragm are opposed by pressures acting on the second diaphragm.

Another object of the invention is to provide embodiments of the invention in which, for example, water, or water and alcohol, or other liquids or fluids, or mercury, may be employed for the purposes set forth, and embodiments of the invention for use with fluid control valves, or with control switches, relays, or other control devices.

Another object of the invention is to provide improved forms of devices having various features of novelty and advantages, and which are particularly characterized by their simplicity in construction, their economy in manufacture, and their efiectiveness in use.

Further objects and advantages of the inven-- tion will appear from the following detailed description, taken in connection with the accompanying drawings which illustrate the manner of constructing and using certain illustrative embodiments of the invention.

In the drawings:

Figure 1 shows more or less diagrammatically thermoelectric control apparatus embodying the present invention as applied for. controlling thesupply of fuel to a main burner having a pilot burner in juxtaposition thereto;

Figure 2 is a diagrammatic view showing'an actuating structure using mercury and applied Figure 3 is a diagrammatic view similar to Figure 2 but showing an actuating structure according to Figure 1, and a second diaphragm which cooperates in the tubular system in such manner that changes in atmospheric pressure affecting the first diaphragm are opposed by pressure acting on the second diaphragm.

Referring first to Figure l of the drawings, the burner shown at l is a main burner. It may be the main burner fora room or space heater, or it may be the burner for a water heater, or for a floor furnace, an oven burner, one or more top burners for a gas range, or any other burner, and of any suitable construction.

A. fuel supply pipe or conduit 2 leads to the burner i for the deliver of gaseous or other fuel thereto, for example, through a mixing chamber 3 to which air is admitted through adjustable air inlets not shown), as Well understood in the art.

The flow of gas through the conduit 2 is controlled by a valve member 4 which is shown in closed position seated upon an annular valve seat 5 at one end of a valve opening 6 within the valve, body shown diagrammatically at lon enlarged scale relative to the burner I. Contiguous sections of the fuel supply pipe 2 are connected to the inlet 8 and outlet 9 of the valve body.

The electromagnet of the thermoelectric control structure shown in Figure 1 comprises a gen erally U-shaped magnet frame it having coils ii wound about the legs thereof and connected in series circuit relation. One side of one coil is connected by a conductor E2 in circuit with one side of a thermoelectric generator 53, and the other side of the other coil is connected by conductors Hi to the other side of the thermoelectric generator H5. The thermoelectric generator I3 is shown in the form of a thermocouple having elements of different thermoelectric characteristics joined at ii to form the hot junction. The thermoelectric generator may be in the form of a thermopile, or of any other suitable form, and is disposed with the hot junction [5 in the pilot flame, or in position to be heated by the pilot flame when it is ignited.

Where the apparatus is used, for example, for controlling a heater, a thermostat 16 or any other control may be connected in series in the thermoelectric circuit to control such circuit, for example, by connecting it between the conductors M. The thermostat 16 may be opened and closed in accordance with the temperature of the room or other space where the heater is a room or space heater, or the thermostat may be arranged to be opened and closed in accordance with the temperature of the water in the tank associatedwith the burner :i where the heater is a water heater, or otherwise as desired. Moreover, a limit control or any other suitable or preferred control or combination of controls may be connected in series in the thermoelectric circuit.

The electromagnet is housed within a downwardly opening cup-shaped shell H which may, for example, be flanged outwardly at its lower end and secured to the adjacent part of the valve body I by a ring nut l8 screwed on the valve body. Where the shell I 1 is formed of metallic material, insulating means may be provided where the conductors I2 and 14 enter the shell as well understood in the art.

The valve member 4' is moved upwardly and downwardly as viewed in Figure l to open and closed positions by a bellows l9. The closed end of the bellows is is secured at 20 to the adjacent end of the valve stem 2 I', and the inwardly opening lower end of the bellows is secured at 22 to the inwardly extending and inwardly opening neck 23 formed integral with a partition E i and disposed at the axis thereof. The partition 2 seats on an annular seat 25 on the valve body and closes the adjacent end of the inlet chamber 28 within the valve body.

Th outer marginal portion of the partition 24 is flanged outwardly. A flexible diaphragm Z1 is fastened marginally to the outer end of the outwardly flanged portion of the partition 24 and, with the partition, forms a closed and sealed liquid or fluid chamber 28. This chamber 28 and the space between the neck 23 and the bellows I9 is filled,'for example, with water, or water and alcohol, or any other suitable liquid or fluid. The partition 24 and diaphragm 21 are secured to the valve body by the ring nut l8.

In order to reduce the amount of volumetric Cal variations in the liquid or fluid body within the chamber 28 with changes in ambient temperatures, a large portion of the chamber 28 may be filled by a non-expansible plug or filler member 25. The plug as may be formed, for example, of an alloy known as Invar, which is an iron, nickel alloy having a composition about 63.8 Fe, 35 Ni, and 0.2 C. This alloy is insensitive to temperature changes.

The device is provided with an armature 38 which is biased downwardly, as viewed in Figure 1, by a coiled spring 3| interposed, for example, between the armature 30 and an annular shoulder 32 on the shell i. The bias of the armature by the spring 3i is in opposition to the magnetic bias of the electromagnet when it is powered or energized by the thermoelectric generator i3.

One of the essential features of the present invention is that the armature 3d moves only through a very minute air gap which is shown more or less illustratively at 33 with the valve member 4 in closed position. This air gap 33 may be of the order of a few ten-thousandths of an inch and preferably attaining one one-thousandth of an inch as maximum spacing. Accordingly, some suitable adjustment may be provided to position the electromagnet relative to the armature 33 and the diaphragm 2'! so that the valve may have a travel into engagement with the valve seat 5 and away from. the valve seat sufiicient to pass gas freely through the valve body i.

As illustrative of one suitable adjustment means for the foregoing purpose, the magnet frame H3 is shown provided with a threaded stem 34 which projects through the end of the shell 27 and has a nut 35 screwed thereon. By turning the nut 35, the position of the pole ends of the magnet frame It may be adjusted toward and away from the armature 3B. A look nut (not shown) or other suitable means may be provided for locking the magnet frame in the desired position.

The pilot burner 31, which is located in juxtaposition to the main burner I for igniting the main burner, is suppliedwith gaseous fuel by a pilot supply pipe 33. The pilot supply pipe 38 may be connected, for example, to the pipe 2 anterior of the valve 4, or through the valve body I, or to any other source of fuel supply. The

thermoelectric generator 13 is disposed with the hot junction or junctions thereof in the pilot flame or in position to be heated by the pilot flame when the pilot burner is ignited.

In order to permit the liquid or other fluid to flow freely in the chamber 28 and around the plug 29 from the large cross-sectional area ofthe chamber to the neck 23 of reduced cross-sectional area, and from the reduced neck to the large cross-sectional area portion of the chamher, the plug 29 may be provided, for example, with slots 39 in opposite surfaces thereof. These slots 39 preferably extend entirely across the opposite faces of the plug 39 for the purpose set forth.

In the operation of the device, with the pilot burner 31 extinguished or the thermostat [6 or other control open, the thermoelectric circuit, which includes the coils l I, is deenergized. At this time the armature 30 is biased to retracted position separated from the pole faces of the magnet frame It! by the very minute amount of the air gap 33. As previously set forth, this gap 33 may attain, for example, a maximum of substantially only 3 of an inch, and the valve 4 will be in engagement with its valve seat 5. As the armature 3!] move to retractedposition it moves, by its cooperation with the diaphragm 21, the diaphragm downwardly as viewed in Figure 1 a substantially equal amount. This reduces the volume of the chamber 28 by approximately the cross-sectional area of the chamber times the minute movement of the armature.

Due to the relatively large cross-sectional area of the chamber 28, the amount of liquid displaced from the chamber 28 into the neck 23 and acting upon the bellows Hi to move the valve 4 downwardly to closed position will be suificient to provide, by the minute movement of the armature, an increased movement of the valve member into engagement with its seat and away from its seat sufiicient to pass gas freely through the valve body for maintaining the desired flame at the main burner A computation has been worked out with a 3-inch diameter diaphragm 2! and -inch diameter bellows I9, and it has been found by comparison of area that over of an inch opening may be obtained by the valve 4.

When the pilot burner 3'! is ignited, the coils l are energized by the heat of the flame of thepilot burner on. the hot junction or junctions of the thermoelectric generator I3. The magnetic flux created by the energization of the windings moves the armature 30 to attracted position relative to the pole faces of the magnet frame I!) against the action of the spring 3|. This increases the volume of the chamber 28 by the cross sectional area of this chamber, times the movement of the armature 30. At this time the pressure of the gas within the inlet chamber 26 of the valve body I, plus any atmospheric pressure, will force the bellows i9 upwardly, and thus move the valve 4 to open position in amount considerably greater than the minute amount of movement of the armature 30 as described in connection with the closing of the valve 4.

It will thus be apparent that the present invention provides, by the very minute movement of the armature, for obtaining increased movement of the valve or other controlling means in amount, for example, for opening and closing the valve 4 suihciently for its intended purpose. Moreover,-

the force of opening of the valve 4 may be substantial inasmuch as the attraction of the armature 3|! may substantially cancel the pressure of the spring 3|.

If the pilot burner 31 is extinguished, the device acts as a safety shutoff device for shutting off the supply of fuel to the main burner by the accompanying deenergization of the thermoelectric the thermoelectric circuit is again closed or en,-

abled by such other control. When the thermoelectric circuit is closed or enabled by such other control device or control devices however, the

valve 4 will operate automatically to open position when the pilot burner 31 is ignited. If the pilot burner is not ignited, the valve 4 will not operate to open position until the pilot burner 31 is ignited and until the thermoelectric circuit is closed or enabled, for example, by the thermostat IE or other control device where such thermostat or other control device is present.

In the embodiment of the invention shown in Figure 2, the electromagnet may correspond, in general, with the electromagnet shown in Figure 1. It has a magnet frame l0 and coils connected in circuit with the thermoelectric generator I 3' by lead conductors 40.

The electromagnet is closed within a container or vessel 4|, and has an armature 42 which, as before, moves only through a very minute air gap of the amount previously set forth or of other desired amount. The armature 42 is connected by a stem 43 to a piston or plunger 44 which operates, for example, in sliding engagement with the adjacent wall of the vessel I which serves as a cylinder for this plunger.

A tubular system has a bottom leg 45, a vertical leg 46 opening downwardly from the bottom of the vessel 4| to one end of the bottom leg, and a second vertical leg 41 extending upwardly to an upper leg 48, which upper leg 48 opens, for example, at its opposite end into the vessel 4| above the plunger 44. In this embodiment of the invention the tubular system may be formed of stainless steel or other suitable material for resisting attack by mercury. The space within the vessel 4| below the plunger 44 is filled with mercury, which also fills the legs 46 and of the tubular system, and extends up into the leg 41, for example, to the position indicated at 49.

An electrode 50 may connect to the tubular leg 4? where this leg is formed of conducting ma terial, or the electrode may extend into this leg and into electrical contact with the mercury 5| therein. In either case, the mercury 5| at the position 49 serves as one of the contacts of the switch or relay. A second electrode 52 may be sealed into the tubular system as, for example,- by a glass seal or other suitable seal. The electrodes 49 and 52 are connected by conductors 53 and 54 in the circuit for the device which it is desired to control.

In operation of the device shown in Figure 2, minute movement of the armature 42 to retracted position produces increased movement of the mercury at the position 49 due to the relatively small cross-sectional area of the tubular system at position 49 as compared with the crosssectional area of cooperation of the plunger 44 with the body of mercury within the vessel 4|. The movement of the armature 42 to retracted position may be limited, for example, by coop eration of the plunger with the bottom of the vessel 4|. or by other suitable stop means coopcrating with the armature or with the plunger. The armature is moved to attracted position by energization of the electromagnet, as in the previous embodiment of the invention, and a spring 55 may be provided for moving the armature to retracted position with accompanying movement of the plunger when the electromagnet is deenergized.

As the mercury in. the leg 41 is forced outwardly upon movement of the armature to retracted position, it contacts the electrode 52 and completes the electric circuit through the conductors 53 and 54. The device may, of course. within the scope of present invention, be ar ranged to make contact and complete the circuit when the armature moves to attracted position. and to open the circuit when the armature moves to retracted position.

The embodiment of the invention shown in;

aeeaesv Figure 3 is similar, in general, to the embodiment of the invention. shown in Figure 2, except that the actuating structure is similar to the actuating structure shown in Figure l, The bellows i9 opens into a vertical tubular leg 55, which in turn opens into the horizontal leg 55 of the tubular system. The horizontal leg 56 opens into a vertical tubular leg 5?. The bellows l9 and the tubular system up to the position indicated at 58 in the vertical leg 5? is filled with mercury. The tubular system and bellows i9 may be formed of stainless steel to resist attack by the mercury.

An electrode as may connect to the tubular leg 51 where this leg is formed of conducting material, or the electrode may extend into this leg and into electrical contact with the mercury 50 therein. In either case, the mercury at the position 58 serves as one or the contacts of the switch or relay. A second electrode may be sealed into the tubular system as, for example, by a glass seal 62 or other suitable seal. The electrodes 53 and 54 are connected by conductors 63v and 6 3 to the circuit which it is desired to control.

' In the device shown in Figure 3, a tubular leg or passage fiilextends from the vertical leg 57 to a casing or chamber 55 provided with a diaphragm 67. This diaphragm Gl' cooper-ates in the tubular system in such manner that changes in atmospheric pressure affecting the first dia phragm (i. e., the diaphragm 2? of the actuator) are opposed by pressure acting on the second diaphragm 51. The tubular leg 65, as well as the chamber 68, and the interior of the vertical leg 51 above the mercury so therein are preferably filled with a suitable gas. In this respect, it is preferable to employ some inert non-oxidizing gas within the system, such, for example, as arson or the like.

The passage 65 may contain a porous plug 68 of such consistency or character that it will pass the gas Within the system freely, but will stop or block off the flow of mercury. A iritted or sintered glass plug is contemplated for this purpose, but this is illustrative and not limiting.

It is believed that the operation of the device shown in Figure 3 will be clear from the descriptions of the operations of the devices shown in Figures 1 and 2.

The embodiments of the invention shown in the drawings are for illustrative purposes only, and it is to be expressly understood that said drawings and the accompanying specification are not to be construed as a definition of the limits or scope of the invention, reference being had to the appended claims for that purpose.

I claim:

1. In a device of the class described, in combination, an electromagnet, an armature biased to retracted position and movable to attracted position by energization of said electromagnet, a fluid containing cylinder having a first relatively small diameter portion and a second relatively large diameter portion between which fluid is adapted to be displaced by the movement of said armature to attracted and retracted positions, and control means operable to one of at least two different positions by the displacement of fluid from the first relatively small diameter portion of the cylinder to the second relatively large diameter portion of the cylinder and operable to the other of such two positions by displacement of fluid from the second relatively large diameter portion of the cylinder to the first relatively small diameter portion of the cylinder, the two difierent positions of the control means being separated by an amount greater than the separation of said armature from said eleotromagnet when said armature is in retracted position.

2. A device according to claim 1 wherein the electromagnet has a winding connected in circuit with a relatively weak source of energy incapable of moving the armature a distance as great as the distance between the two positions of the control means.

3. A device according to claim 1 wherein the electromagnet has a winding connected in circuit with a thermoelectric generator for energization thereby.

d. A device according to claim. 1 wherein the electromagnet has a winding connected in circuit with a thermoelectric generator for energization thereby, and condition responsive means in'the circuit which includes the winding of the electromagnet and the thermoelectric generator.

5.. A control device according to claim 1 wherein the control means comprises a safety shut-cit valve connected to a flexible bellows responsive to the fluid displaced from the relatively large diameter portion of the cylinder to the relatively small diameter portion of the cylinder, and wherein at least one large diameter wall of the large diameter portion of the cylinder is formed by a flexible diaphragm actuated by the relatively minute movement of the armature to retracted position.

6. A control device according to claim 1 wherein the control means comprises a safety shut-off valve connected to a flexible bellows responsive to the fluid displaced from the relatively large diameter portion of the cylinder to the relatively small diameter portion of the cylinder, and wherein at least one large diameter wall of the large diameter portion of the cylinder is formed by a flexible diaphragm actuated by the relatively minute movement of the armature to retracted position, the relatively large diameter portion 01' the cylinder containing a non-expansible fille1 member for reducing the amount of volumetric variations in the fluid in said portion of the cylinder.

7. A control device according to claim 1 wherein the control means comprises a safety shut-oil valve connected to a flexible bellows responsive to the fluid displaced from the relatively large diameter portion of the cylinder to the relatively small diameter portion of the cylinder, and wherein at least one large diameter wall of the large diameter portion of the cylinder is formed by a flexible diaphragm actuated by relatively minute movement of the armature to retracted position, the relatively large diameter portion of the cylinder containing a non-expansible filler member for reducing the amount of volumetric variations in the fluid in said portion of the cylinder, said filler member having slots extending across its opposite surfaces to permit free flow of the fluid around the filler member.

8. -A control device according to claim 1 wherein the control means comprises spaced contacts, and a body of mercury disposed in the cylinder portion of relatively small diameter and actuated in a direction to control connection between said contacts by displacement. of fluid between the relatively large diameter and relatively small diameter portions of the cylinder.

9. A control device according to claim lwherein the control means comprises spaced contacts, and a body of mercury disposed in the cylinder portion of relatively small diameter and actuated in a direction to control connection between said contacts by displacement of fluid between the relatively large diameter and relatively small diameter portions of the cylinder, the relatively small diameter portion of the cylinder having an upper leg placing the small diameter portion of the cylinder above the body of mercury therein in communication with the large diameter portion of the cylinder above the means for displacing fluid from the large diameter portion of the cylinder to the small diameter portion of the cylinder.

10. A control device according to claim 1 wherein the control means comprises spaced contacts, a body of mercury disposed in the cylinder portion of relatively small diameter and actuated in a direction to control connection between said contacts by displacement of fluid between the relatively large diameter and the relatively small diameter portions of the cylinder, and a connected leg placing a diaphragm chamber having a diaphragm responsive to atmospheric pressure in communication with the small diameter portion of the cylinder between the spaced contacts.

11. A control device according to claim 1 wherein the control means comprises spaced contacts, a body of mercury disposed in the cylinder portion of relatively small diameter and actuated in a direction to control connection between said contacts by displacement of fluid between the relatively large diameter and the relatively small diameter portions of the cylinder, a connected leg placing a diaphragm chamber having a diaphragm responsive to atmospheric pressure in communication with the small diameter portion of the cylinder between the spaced contacts, and a plug in said connected leg of a character to pass gas freely but which will block the flow of mercury.

12. A control device comprising, in combination, a valve body having an inlet, and outlet, and a port provided with a valve seat, said valve 10 body having an outwardly opening tubular part in alignment with the valve seat, a partition seated on the outer end of said tubular part, said partition having an outwardly extending marginal flange of relatively large diameter and an inwardly extending tubular neck of relatively small diameter, a valve member movable into and out of cooperation with the valve seat, a flexible bellows of relatively small diameter disposed within said relatively small diameter tubular neck and connected to said valve member, a flexible diaphragm secured marginally over the marginal flange of said partition and with said partition defining a relatively large diameter chamber containing a fluid which is displaced from said large diameter chamber into said tubular neck and from said tubular neck into said large diameter chamber, an electromagnet comprising a magnet frame and a windin therefor, and a relatively large diameter armature for said electromagnet, said armature, when in retracted position, being spaced from the magnet frame by a minute air gap and acting against said diaphragm to displace fluid from said relatively large diameter chamber into said relatively small diameter neck whereby to impart increased movement to said bellows to close said valve.

SEBASTIAN KARRER.

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